1. Field of the Invention
The invention relates to an apparatus and method for controlling a display and, more particularly, to an apparatus and method for controlling a stereo video display with non-stereo video source.
2. Description of the Related Art
The reason why human being has stereoscopic vision is that both human eyes have individual perceptions of the outside world. That is, the left eye sees the scenery on the left; the right eye sees the scenery on the right, and there exists some angle diversities between the two. After a spontaneous fusing process of the brain, it shows stereoscopic scenery in the brain.
Stereoscopic images can be generated by applying a similar principle. By way of showing images for the left eye and the right eye independently, a stereo video display can show different images for each eye of the observer. For example, images for left and right eyes can be alternately played on the display and, in coordination with a synchronized shutter viewer (SSV) such as an LC shutter glasses, the right eye is covered when the display is playing left-eye images, and the left eye is covered when the display is playing right-eye images. That is, the left eye sees only images for the left eye, and the right eye sees only images for the right eye. Continuously repeating the process of displaying images alternately at a speed faster than human vision suspension, the stereo video display enables observers to perceive stereoscopic images.
Referring to FIGS. 1 and 2, a conventional technique for displaying stereoscopic images provides in a memory 1 with two memory blocks B1 and B2 for storing data for sinistral images and data for dextral images. A display 8 shows the sinistral and dextral images stored in the memory blocks B1 and B2 alternately. As shown in FIG. 1, the display 8 shows the sinistral image stored in the memory block B1. As shown in FIG. 2, the display 8 shows the dextral image stored in the memory block B2. When displaying different images, a synchronized shutter viewer (SSV) 9 performs a switching function simultaneously, so that the sinistral image only gets into the observer's left eye, and the dextral image only gets into observer's right eye.
Referring to FIG. 3, when the video source is a non-stereo video source, the stereo video display can make two consecutive frames as a sinistral image and a dextral image, respectively, to display a stereoscopic image. Similar to FIGS. 1 and 2, the memory 1 shown in FIG. 3 also has two memory blocks B1 and B2 as buffers. However, each of the buffers B1 and B2 stores two frames. When showing images stored in the memory block B1, frames F1 and F2 are alternately displayed on the display 8 as the sinistral image and dextral image. When showing images stored in the memory block B2, frames F2 and F3 are alternately displayed on the display 8 as the next sinistral image and dextral image.
Due to little differences existed between two consecutive frames, the stereo video display can provide different image perceptions for each eye of the observer through the above-mentioned method and in coordination with an SSV. When the preparation for the next frame (that is, frame F3) in the memory block B2 is completed, the stereo video display can switch to the memory block B2 and alternately display frames F2 and F3 on the display 8. At the same time, a next frame is being prepared in the memory block B1. By this, stereoscopic images can be played continuously after reading the non-stereo video source.
However, one problem of the above-mentioned method for displaying stereoscopic images is that, when the movement direction of an object in the image is changed, the observer may experience a sudden change in the stereoscopic effect. For example, an object was moving formerly from left to right, and the observer's perception of the object location was at the “front” of the display. When the object changes its moving direction and moves from right to left, the observer will experience a sudden change in the perception of the object location as at the “back” of the display. This problem may result in that the observer is not able to experience a consistent stereoscopic effect, and thus causing confusions to the observer.